Light-emitting device and light source module including the same

ABSTRACT

A light source module is provided. The light source module includes a printed circuit board; a light-emitting device mounted on the printed circuit board, the light-emitting device including a plurality of cell blocks, each of which includes a plurality of light-emitting cells; and a plurality of controllers mounted on the printed circuit board, each of which is configured to drive a cell block corresponding thereto, from among the plurality of cell blocks. The plurality of cell blocks are electrically isolated from each other, the plurality of cell blocks include a first cell block and a second cell block, and a number of first light-emitting cells included in the first cell block is less than a number of second light-emitting cells included in the second cell block.

CROSS-REFERENCE TO RELATED THE APPLICATION

This application claims priority from Korean Patent Application No.10-2020-0063276, filed on May 26, 2020, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference in its entirety.

BACKGROUND 1. Field

Apparatuses and methods consistent with example embodiments relate to alight-emitting device and a light source module including the same, andmore particularly, to a light-emitting device including a plurality ofblocks including a plurality of light-emitting cells, and a light sourcemodule including the light-emitting device.

2. Description of the Related Art

Semiconductor light-emitting devices include elements such aslight-emitting diodes (LEDs), and are increasingly being used as lightsources because the semiconductor light-emitting devices have manyadvantages such as low power consumption, high brightness, and longlifespans. In recent years, there has been a growing interest insemiconductor light-emitting devices as units capable of replacing theexisting halogen or xenon lamps used as light sources for headlamps ortail lamps for vehicles.

When a semiconductor light-emitting device is applied as a light sourceto a lighting apparatus, it may be necessary to adjust brightness, alight orientation angle, and a light irradiation angle of thesemiconductor light-emitting device to desired values. In particular, aheadlamp or a tail lamp for a vehicle requires a semiconductorlight-emitting device capable of adjusting the brightness of lightaccording to surrounding conditions.

SUMMARY

One or more example embodiments provide a light-emitting device, whichhas improved optical characteristics and reliability, and a light sourcemodule including the light-emitting device.

According to an aspect of an example embodiment, a light source moduleincludes a printed circuit board; a light-emitting device mounted on theprinted circuit board, the light-emitting device including a pluralityof cell blocks, each of which includes a plurality of light-emittingcells; and a plurality of controllers mounted on the printed circuitboard, each of which is configured to drive a cell block correspondingthereto, from among the plurality of cell blocks. The plurality of cellblocks are electrically isolated from each other, the plurality of cellblocks include a first cell block and a second cell block, and a numberof first light-emitting cells included in the first cell block is lessthan a number of second light-emitting cells included in the second cellblock.

According to an aspect of an example embodiment, a light-emitting deviceincludes: a plurality of cell blocks electrically isolated from eachother, each of which includes a plurality of light-emitting cells; and aplurality of pads configured to electrically connect the plurality ofcell blocks to an external device. The plurality of cell blocks includea first cell block and a second cell block, and a number of firstlight-emitting cells included in the first cell block is less than anumber of second light-emitting cells included in the second cell block.

According to an aspect of an example embodiment, a light source moduleincludes: a printed circuit board; a light-emitting device mounted onthe printed circuit board, the light-emitting device including aplurality of cell blocks, each of which includes a plurality oflight-emitting cells; and a plurality of controllers mounted on theprinted circuit board, each of which is configured to drive a cell blockcorresponding thereto, from among the plurality of cell blocks. Theplurality of cell blocks are electrically isolated from each other, andthe plurality of cell blocks are arranged in a first row and a secondrow, and a number of light-emitting cells included in cell blocksarranged in the first row is less than a number of light-emitting cellsincluded in cell blocks arranged in the second row.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features will become more apparent fromthe following description of example embodiments with reference to theaccompanying drawings in which:

FIG. 1 is a block diagram of a configuration of a light source moduleaccording to an example embodiment;

FIG. 2 is a perspective view of a configuration of a light source moduleaccording to an example embodiment;

FIG. 3 is a block diagram for explaining the connection of controllersto a light-emitting device in a light source module according to anexample embodiment;

FIG. 4 is a perspective view of a configuration of a light-emittingdevice according to an example embodiment;

FIGS. 5 and 6 are circuit diagrams for explaining connectionrelationships between light-emitting cells in a light-emitting deviceaccording to an example embodiment;

FIGS. 7 to 9 are diagrams of a light-emitting device according toexample embodiments;

FIGS. 10 and 11 are circuit diagrams for explaining a connectionrelationship between light-emitting cells included in a light-emittingdevice according to an example embodiment;

FIGS. 12 and 13 are diagrams of light-emitting devices according toexample embodiments;

FIGS. 14 and 15 are cross-sectional views of light source modules,according to example embodiments;

FIG. 16 is a schematic perspective view of a lighting apparatusincluding a light-emitting device, according to an example embodiment;

FIG. 17 is a schematic perspective view of a flat-panel lightingapparatus including a light-emitting device, according to an exampleembodiment; and

FIG. 18 is an exploded perspective view of a lighting apparatusincluding a light-emitting device, according to an example embodiment.

DETAILED DESCRIPTION

The above and other aspects and features will become more apparent bydescribing example embodiments in detail with reference to theaccompanying drawings. It will be understood that when an element orlayer is referred to as being “over,” “above,” “on,” “connected to” or“coupled to” another element or layer, it can be directly over, above,on, connected or coupled to the other element or layer or interveningelements or layers may be present. In contrast, when an element isreferred to as being “directly over,” “directly above,” “directly on,”“directly connected to” or “directly coupled to” another element orlayer, there are no intervening elements or layers present. The samereference numerals are used to denote the same elements in the drawings,and repeated descriptions thereof will be omitted.

FIG. 1 is a block diagram of a configuration of a light source module 10according to an example embodiment.

Referring to FIG. 1, the light source module 10 may include alight-emitting device 100 and a driving circuit 200.

The light-emitting device 100 may include a cell array CA including aplurality of light-emitting cells. The cell array CA included in thelight-emitting device 100 may include a plurality of cell blocks BLK. Inan example embodiment, the plurality of cell blocks BLK may beelectrically isolated from each other.

The driving circuit 200 may be connected to a power supply. The powersupply may generate an input voltage required for an operation of thelight-emitting device 100. In an example embodiment, when the lightsource module 10 is a headlamp for a vehicle, the power supply mayinclude a battery mounted in the vehicle. In an example embodiment, whenthe light source module 10 is a household or industrial lightingfixture, the light source module 10 may further include analternating-current (AC) power supply configured to generate an ACvoltage, a rectifying circuit configured to rectify the AC voltage andgenerate a direct-current (DC) voltage, and a voltage regulatingcircuit.

The driving circuit 200 may include a plurality of controllers 210. Eachof the plurality of controllers 210 may include an integrated circuit(IC).

The plurality of controllers 210 may drive the cell array CA included inthe light-emitting device 100. In an example embodiment, each of thecontrollers 210 may be electrically connected to a corresponding one ofthe plurality of cell blocks BLK and control operations oflight-emitting cells included in the corresponding cell block BLK. In anexample embodiment, the number of controllers 210 may be equal to thenumber of cell blocks BLK included in the light-emitting device 100.However, example embodiments are not limited thereto. For example, thenumber of controllers 210 may be different from the number of cellblocks BLK.

FIG. 2 is a perspective view of a configuration of a light source module10 according to an example embodiment.

Referring to FIG. 2, the light source module 10 may include alight-emitting device 100 and a plurality of controllers (e.g., first toninth controllers 210_1 to 210_9), which are mounted on a printedcircuit board PCB. In an example embodiment, the light-emitting device100 may include one chip, and the light source module 10 may include thelight-emitting device 100 including one chip.

The light-emitting device 100 may include a cell array CA in which aplurality of light-emitting cells are arranged in a matrix form. Thecell array CA may include a plurality of cell blocks (e.g., first toninth cell blocks BLK1 to BLK9). Although nine cell blocks BLK1 to BLK9are illustrated in FIG. 2, example embodiments are not limited thereto,and the number and arrangement of cell blocks (e.g., BLK1 to BLK9) maybe changed.

The first to ninth cell blocks BLK1 to BLK9 may be electrically isolatedfrom each other. That is, light-emitting cells included in differentcell blocks may be electrically isolated from each other.

In an example embodiment, the light-emitting device 100 may have arectangular shape having shorter sides in a second direction Y than in afirst direction X. The first direction X and the second direction Y maybe parallel to a main surface of a printed circuit board PCB andperpendicular to each other.

In an example embodiment, in the light-emitting device 100, the first toninth cell blocks BLK1 to BLK9 may be arranged in a first row and asecond row. In this case, each of the first row and the second row mayrefer to cell blocks arranged in parallel in the first direction X.Because the first to ninth cell blocks BLK1 to BLK9 are arranged in tworows, it may be structurally easy to form a plurality of pads configuredto connect the light-emitting device 100 to the first to ninthcontrollers 210_1 to 210_9.

The light-emitting cells may be arranged in consideration of a lightdistribution type required for the light source module 10. The number oflight-emitting cells included in cell blocks arranged in the first row(e.g., BLK1 to BLK4) may be less than the number of light-emitting cellsincluded in cell blocks arranged in the second row (e.g., BLK5 to BLK9).The number of cell blocks arranged in the first row may be differentfrom the number of cell blocks arranged in the second row. For example,the first to fourth cell blocks BLK1 to BLK4 may be sequentiallyarranged in the first row in the first direction X, and the fifth toninth cell blocks BLK5 to BLK9 may be sequentially arranged in thesecond row in an opposite direction to the first direction X.

In an example embodiment, the number of light-emitting cells included inthe first cell block BLK1 arranged at one end of the first row may beless than the number of light-emitting cells included in another one ofthe first to ninth cell blocks BLK1 to BLK9. For example, the number oflight-emitting cells in the first cell block BLK1 may be less than thenumber of light-emitting cells in the second cell block BLK2, which isadjacent to the first cell block BLK1.

In an example embodiment, the number of light-emitting cells included inthe seventh cell block BLK7 in the center of the second row may be lessthan the number of light-emitting cells included in another one of thefirst to ninth cell blocks BLK1 to BLK9. For example, the number oflight-emitting cells included in the seventh cell block BLK7 may be lessthan the number of light-emitting cells included in the sixth cell blockBLK6, which is adjacent to the seventh cell block BLK7, or be less thanthe number of light-emitting cells included in the eighth cell blockBLK8, which is adjacent to the seventh cell block BLK7.

In the light source module 10, the light-emitting cells may be arrangedin consideration of a light distribution type required for the lightsource module 10. For example, when the light source module 10 is usedas a headlamp for a vehicle, it may be relatively unnecessary toirradiate light to an upper outer area in front of a user in a directionin which the user travels. The first cell block BLK1 and the fourth cellblock BLK4, which are at both ends of the first row, may include asmaller number of light-emitting cells than other cell blocks, and thus,the light source module 10 may not separately irradiate light tounnecessary areas.

In addition, for example, when the light source module 10 is used as theheadlamp for the vehicle, the light source module 10 may need toirradiate light having a relatively high light intensity to a centralarea of a road in front of the user in the direction in which the usertravels. The seventh cell block BLK7 in the center of the second row mayinclude a relatively small number of light-emitting cells. Even when thelight source module 10 is controlled to irradiate light having a highintensity by applying a relatively large current to the seventh cellblock BLK7, power consumption by the seventh cell block BLK7 may bereduced because the seventh cell block BLK7 includes fewerlight-emitting cells.

Each of the first to ninth controllers 210_1 to 210_9 may controllight-emitting cells included in a cell block corresponding thereto,from among the first to ninth cell blocks BLK1 to BLK9, to operate. Forexample, the first controller 210_1 may be electrically connected to thefirst cell block BLK1 and control an operation of the first cell blockBLK1. The second controller 210_2 may be electrically connected to thesecond cell block BLK2 and control an operation of the second cell blockBLK2. The description of the first and second controllers 210_1 and210_2 may be equally applied to the third to ninth controllers 210_3 to210_9.

In the light-emitting device 100, the plurality of light-emitting cellsin the cell array CA may be subdivided into the first to ninth cellblocks BLK1 to BLK9, and operations of the first to ninth cell blocksBLK1 to BLK9 may be controlled by respectively different controllers.Thus, it may become easy to control a light emitting operation of thelight-emitting device 100. The control of brightness of thelight-emitting device 100 may be subdivided, and a brightness adjustingspeed may be increased.

In an example embodiment, the first to ninth controllers 210_1 to 210_9may be arranged in an order in which cell blocks corresponding to thefirst to ninth controllers 210_1 to 210_9 are arranged. For example, inthe light-emitting device 100, the first to fourth cell blocks BLK1 toBLK4 may be sequentially arranged in the first direction X, and thefirst to fourth controllers 210_1 to 210_4 corresponding to the first tofourth cell blocks BLK1 to BLK4 may also be sequentially arranged in thefirst direction X. Additionally, in the light-emitting device 100, thefifth to ninth cell blocks BLK5 to BLK9 may be sequentially arranged inan opposite direction to the first direction X, and the fifth to ninthcontrollers 210_5 to 210_9 corresponding to the fifth to ninth cellblocks BLK5 to BLK9 may also be sequentially arranged in the oppositedirection to the first direction X. In the light source module 10, thefirst to ninth controllers 210_1 to 210_9 and the first to ninth cellblocks BLK1 to BLK9 may be arranged such that the order in which thefirst to ninth controllers 210_1 to 210_9 are arranged corresponds tothe order in which the first to ninth cell blocks BLK1 to BLK9. Thus, itmay become easy to form wirings or wires configured to electricallyconnect the first to ninth controllers 210_1 to 210_9 to the first toninth cell blocks BLK1 to BLK9.

However, the arrangement of the plurality of controllers 210_1 to 210_9is not limited thereto, and only some of the first to fourth controller210_1-210_4 may be sequentially arranged in the first direction X, andonly some of the fifth to ninth controllers 210_5 to 210_9 may besequentially arranged in an opposite direction to the first direction X.

In an example embodiment, the number of controllers (e.g., 210_1 to210_9) may be equal to the number of cell blocks (e.g., BLK1 to BLK9).However, example embodiments are not limited thereto. At least twodifferent controllers may be connected to one cell block and control theone cell block. Alternatively, one controller may control at least twodifferent cell blocks.

The light-emitting device 100 may be mounted on a central area CA_P ofthe printed circuit board PCB, and the first to ninth controllers 210_1to 210_9 may be in first and second peripheral areas PA_P1 and PA_P2 ofthe printed circuit board PCB adjacent the light-emitting device 100.For example, the first to fourth controllers 210_1 to 210_4 may be inthe first peripheral area PA_P1, and the fifth to ninth controllers210_5 to 210_9 may be in the second peripheral area PA_P2. Because thelight-emitting device 100 is interposed between the first to ninthcontrollers 210_1 to 210_9 in the first and second peripheral areasPA_P1 and PA_P2 of the printed circuit board PCB, it may become easy toform wirings or wires configured to electrically connect the first toninth controllers 210_1 to 210_9 to the first to ninth cell blocks BLK1to BLK9.

In an example embodiment, the light-emitting device 100 may overlap thefirst to ninth controllers 210_1 to 210_9 in a direction (e.g., thefirst direction X or the second direction Y) parallel to the mainsurface of the printed circuit board PCB. In an example embodiment, thesecond peripheral area PA_P2, the central area CA_P, and the firstperipheral area PA_P1 may be sequentially arranged in the seconddirection Y.

In the light source module 10, one light-emitting device 100 includinglight-emitting cells configured to emit light may be in the central areaCA_P of the printed circuit board PCB, and the first to ninthcontrollers 210_1 to 210_9, which are configured to drive thelight-emitting device 100 and respectively include separate chips, maybe in the first and second peripheral areas PA_P1 and PA_P2. Because thelight-emitting device 100 including the plurality of light-emittingcells and the first to ninth controllers 210_1 to 210_9 are implementedas separate chips, designing the first to ninth controllers 210_1 to210_9 may not be affected by the structures of the plurality oflight-emitting cells. Accordingly, the design efficiency of the first toninth controllers 210_1 to 210_9 may be increased.

In addition, the light-emitting device 100 may be implemented as one LEDchip and arranged in the central area CA_P of the printed circuit boardPCB, and thus, light emitted from the light source module 10 may beconcentrated in the central area CA_P. Because the emitted light isconcentrated in the central area CA_P, the number of additionalcomponents (e.g., lenses) configured to condense the emitted light maybe reduced. For instance, the light source module 10 may not includelenses. As the number of lenses included in the light source module 10increases, the amount of light lost by the lenses may increase. Thus,the luminous efficiency of the light source module 10 may increase.

The light source module 10 may further include an input unit configuredto receive signals required for operations of the light source module 10from the outside. The first to ninth controllers 210_1 to 210_9 mayreceive control signals from the input unit, and the first to ninthcontrollers 210_1 to 210_9 may control operations thereof in response tothe control signals.

In an example embodiment, the first to ninth controllers 210_1 to 210_9may be electrically connected to each other in sequential order. Forexample, the first controller 210_1 may be electrically connected to thesecond controller 210_2, the second controller 210_2 may be electricallyconnected to the first controller 210_1 and the third controller 210_3,and the third controller 210_3 may be electrically connected to thesecond controller 210_2 and the fourth controller 210_4. The firstcontroller 210_1 may receive a control signal from the input unit andtransmit the control signal to the second controller 210_2, and thesecond controller 210_2 may receive a control signal from the firstcontroller 210_1 and transmit the control signal to the third controller210_3. The description of the first and second controllers 210_1 and210_2 may be equally applied to the third to ninth controllers 210_3 to210_9.

The printed circuit board PCB may include a metal and a metal compound.The printed circuit board PCB may be a metal-core printed circuit board(MCPCB), which includes, for example, copper (Cu).

In an example embodiment, the printed circuit board PCB may be aflexible printed circuit board (FPCB), which may be flexible and easilymodified into various shapes. In addition, the printed circuit board PCBmay be a FR4-type PCB and include a resin material including epoxy,triazine, silicon, and polyimide or a ceramic material, such as siliconnitride, aluminum nitride (AlN) and aluminum oxide (Al₂O₃).

FIG. 3 is a block diagram for explaining the connection of controllersto a light-emitting device 100 in a light source module 10 according toan example embodiment. Only a first cell block and a second cell blockconnected to a first controller and a second controller are illustratedin FIG. 3 for brevity, and the same description may be applied to othercontrollers (e.g., the third to ninth 210_3 to 210_9) and other cellblocks (e.g., the third to ninth BLK3 to BLK9).

Referring to FIG. 3, the light-emitting device 100 may include a firstcell block BLK1 including a plurality of first light-emitting cells anda second cell block BLK2 including a plurality of second light-emittingcells. The light-emitting device 100 may include a plurality of firstpads PAD1 connected to the first cell block BLK1 and a plurality ofsecond pads PAD2 connected to the second cell block BLK2.

In an example embodiment, the number of first light-emitting cells inthe first cell block BLK1 may be less than the number of secondlight-emitting cells in the second cell block BLK2. The number of firstpads PAD1 connected to the first cell block BLK1 may be less than thenumber of second pads PAD2 connected to the second cell block BLK2.Although FIG. 3 illustrates a case in which the number of first padsPAD1 is one less than the number of second pads PAD2, exampleembodiments are not limited thereto, and the number of first pads PAD1may at least two less than the number of second pads PAD2.

A first controller 210_1 may be connected to a plurality of firstchannels CH11 to CH1 n and drive the first cell block BLK1, which is acell block corresponding to the first controller 210_1, through at leastsome (e.g., CH11 to CH1 n-1) of the plurality of first channels CH11 toCH1 n. The first controller 210_1 may apply a voltage to the first cellblock BLK1 corresponding thereto through the at least some firstchannels CH11 to CH1 n-1 and adjust the intensity of light emitted fromthe first cell block BLK1.

A second controller 210_2 may be connected to a plurality of secondchannels CH21 to CH2 n and drive a second cell block BLK2, which is acell block corresponding to the second controller 210_2, through atleast some of the plurality of second channels CH21 to CH2 n. The secondcontroller 210_2 may apply a voltage to the second cell block BLK2corresponding thereto through the at least some of the second channelsCH21 to CH2 n and adjust the intensity of light emitted from the secondcell block BLK2.

In an example embodiment, the plurality of first channels CH11 to CH1 nconnected to the first controller 210_1 may be different channels fromthe plurality of second channels CH21 to CH2 n connected to the secondcontroller 210_2. Accordingly, the first controller 210_1 and the secondcontroller 210_2, which are different controllers, may individuallycontrol cell blocks corresponding respectively thereto.

In an example embodiment, the first controller 210_1 and the secondcontroller 210_2 may be connected to the same number of channels. Forexample, the first controller 210_1 may be connected to n first channelsCH11 to CH1 n and apply a voltage to each of the first channels CH11 toCH1 n. The second controller 210_2 may be connected to n second channelsCH21 to CH2 n and apply a voltage to each of the second channels CH21 toCH2 n.

In an example embodiment, the number (e.g., (n-1)) of first pads PAD1may be less than the number (e.g., n) of first channels CH11 to CH1 nconnected to the first controller 210_1. At least one channel (e.g., CH1n) of the plurality of first channels CH11 to CH1 n may not be connectedto the plurality of first pads PAD1 but be electrically isolated fromthe first cell block BLK1. Accordingly, the number of channels connectedto the first to ninth controllers 210_1 to 210_9 of the light sourcemodule 10 of FIG. 2 may not correspond to the number of pads formed inthe light-emitting device 100.

However, example embodiments are not limited to the illustration of FIG.3. Because the number of first light-emitting cells included in thefirst cell block BLK1 is less than the number of second light-emittingcells included in the second cell block BLK2, the number of firstchannels CH11 to CH1 n connected to the first controller 210_1configured to control an operation of the first cell block BLK1 may beless than the number of second channels CH21 to CH2 n connected to thesecond controller 210_2 configured to control an operation of the secondcell block BLK2.

FIG. 4 is a perspective view of a configuration of a light-emittingdevice 100 according to an example embodiment.

Referring to FIG. 4, the light-emitting device 100 may include a cellarray region PXR in which a cell array CA is formed and first and secondpad regions PDR1 and PDR2 in which a plurality of pads PAD are formed.The cell array region PXR may be in a central area of the light-emittingdevice 100, and the first and second pad regions PDR1 and PDR2 may be ina peripheral area surrounding the central area. For instance, the secondpad region PDR2, the cell array region PXR, and the first pad regionPDR1 may be sequentially arranged in a second direction Y.

The cell array CA may include a plurality of cell blocks (e.g., first toninth cell blocks BLK1 to BLK9). In this case, the first to ninth cellblocks BLK1 to BLK9 may be electrically isolated from each other.Although a total of nine cell blocks BLK1 to BLK9 are illustrated inFIG. 4, the light-emitting device 100 is not limited thereto, and thenumber and arrangement of cell blocks (e.g., BLK1 to BLK9) may bechanged.

The first to ninth cell blocks BLK1 to BLK9 may be arranged in a firstrow and a second row, which are arranged in parallel to each other inthe second direction Y. For example, the first to fourth cell blocksBLK1 to BLK4 may be arranged in the first row, and the fifth to ninthcell blocks BLK5 to BLK9 may be arranged in a second row. At least oneof the plurality of cell blocks BLK1 to BLK9 may include a differentnumber of light-emitting cells 111 from other cell blocks. In an exampleembodiment, the first cell block BLK1 and the fourth cell block BLK4 atboth ends of the first row may include a smaller number light-emittingcells 111 than at least one of other cell blocks. For example, the firstcell block BLK1 and the fourth cell block BLK4, which are at both endsof the cell array CA, may include a smaller number of light-emittingcells 111 than other cell blocks positioned adjacent thereto. The firstcell block BLK1 may include a smaller number of light-emitting cells 111than the second cell block BLK2, which is adjacent to the first cellblock BLK1 in a first direction X. Alternatively, the first cell blockBLK1 may include a smaller number of light-emitting cells 111 than theninth cell block BLK9, which is adjacent to the first cell block BLK1 inan opposite direction to the second direction Y. The fourth cell blockBLK4 may include a smaller number of light-emitting cells 111 than thethird cell block BLK3, which is adjacent to the fourth cell block BLK4in an opposite direction to the first direction X. Alternatively, thefourth cell block BLK4 may include a smaller number of light-emittingcells 111 than the fifth cell block BLK5, which is adjacent to thefourth cell block BLK4 in an opposite direction to the second directionY.

In an example embodiment, the seventh cell block BLK7 in the center ofthe cell array CA may include a smaller number of light-emitting cells111 than at least one of other cell blocks. For example, the seventhcell block BLK7 may include a smallest number of light-emitting cells111 from among the first to ninth cell blocks BLK1 to BLK9.

FIG. 4 illustrates an example in which each of the second, third, fifth,sixth, eighth, and ninth cell blocks BLK2, BLK3, BLK5, BLK6, BLK8, andBLK9 includes twelve light-emitting cells 111, each of the first andfourth cell blocks BLK1 and BLK4 includes eleven light-emitting cells,and the seventh cell block BLK7 includes eight light-emitting cells,however example embodiments are not limited thereto. In this regard,number of light-emitting cells 111 included in each of the first toninth cell blocks BLK1 to BLK9 may be variously selected.

In an example embodiment, from among light-emitting cells included incell blocks arranged in the first row, light-emitting cells adjacentlyarranged in the second direction Y may be driven (or turned on) or maynot be driven (or turned off) simultaneously. In an example embodiment,partition walls may not be formed between the light-emitting cellsadjacently arranged in the second direction Y, from among thelight-emitting cells included in the cell blocks arranged in the firstrow. In an example embodiment, the first to ninth cell blocks BLK1 toBLK9 may be arranged in a rectangular shape such that the length L1 ofthe light-emitting device 100 in the first direction X is greater than alength L2 of the light-emitting device 100 in the second direction Y.For example, the first to ninth cell blocks BLK1 to BLK9 may be arrangedin a total of two rows, for example, a first row and a second row.

In an example embodiment, the length L1 of the light-emitting device 100in the first direction X may be about 1.1 times or more the length L2 ofthe light-emitting device 100 in the second direction Y. In an exampleembodiment, the length L1 of the light-emitting device 100 in the firstdirection X may be about 100 times or less the length L2 of thelight-emitting device 100 in the second direction Y. According to anexample embodiment, a thickness of the light-emitting device 100 (i.e.,a length of the light-emitting device 100 in a third direction Z) may beseveral tens of μm to several hundreds of μm and may be less than orequal to about 1/10 of the length L1 of the light-emitting device 100 inthe first direction X. Because the light-emitting device 100 having theabove-described dimensions has dimensions optimized for resistance tophysical stress, the warpage of the light-emitting device 100 may beminimized.

The first to fourth cell blocks BLK1 to BLK4 may be sequentiallyarranged in the first row in the first direction X, and the fifth toninth cell blocks BLK5 to BLK9 may be sequentially arranged in thesecond row in an opposite direction to the first direction X. AlthoughFIG. 4 illustrates the first to ninth cell blocks BLK1 to BLK9 arrangedin two rows, example embodiments are not limited thereto, and the cellarray CA may include the first to ninth cell blocks BLK1 to BLK9arranged in at least three rows.

The first to fourth cell blocks BLK1 to BLK4 arranged in the first rowmay be electrically connected to first to fourth controllers (e.g.,210_1 to 210_4 of FIG. 2) through the plurality of pads PAD arranged inthe first pad region PDR1. The fifth to ninth cell blocks BLK5 to BLK9arranged in the second row may be electrically connected to fifth toninth controllers (e.g., 210_5 to 210_9 of FIG. 2) through the pluralityof pads PAD arranged in the second pad region PDR2.

In the light-emitting device 100, the first and second pad regions PDR1and PDR2 may not be in the cell array region PXR but be arranged inparallel with each other and extend in the second direction Y. That is,the first and second pad regions PDR1 and PDR2 in which the plurality ofpads PAD are arranged may not overlap the cell array region PXR in thethird direction Z, which is perpendicular to a main surface of asubstrate. Because the light-emitting device 100 includes the first andsecond pad regions PDR1 and PDR2 separately from the cell array regionPXR, the density of the light-emitting cells 111 in the cell arrayregion PXR may be increased. Furthermore, a plurality of pads PAD may bein the peripheral area of the light-emitting device 100, and thus, itmay be easy to form components (e.g., bonding wires) configured todriving chips to the plurality of pads PAD.

In example embodiments, in a view from above, an area of the cell arrayregion PXR may be in a range of about 50% to about 90% of a total areaof the light-emitting device 100, and an area of the first and secondpad regions PDR1 and PDR2 may be in a range of about 10% to about 50% ofthe total area of the light-emitting device 100, without being limitedthereto.

FIGS. 5 and 6 are circuit diagrams for explaining connectionrelationships between light-emitting cells in a light-emitting device100 according to an example embodiment. FIGS. 5 and 6 are equivalentcircuit diagrams of the first cell block BLK1 and the second cell blockBLK2 of FIG. 4. In FIGS. 5 and 6, one light-emitting cell may correspondto one diode. The description of the first and second cell blocks BLK1and BLK2 of FIGS. 5 and 6 may be equally applied to the third to ninthcell blocks BLK3 to BLK9 of FIG. 4.

Referring to FIGS. 4 and 5, the first cell block BLK1 may include aplurality of first light-emitting cells 111_1, each of which isimplemented as an LED, and the second cell block BLK2 may include aplurality of second light-emitting cells 111_2, each of which isimplemented as an LED. The number of first light-emitting cells 111_1may be less than the number of second light-emitting cells 111_2. Thefirst cell block BLK1 and the second cell block BLK2 may be electricallyinsulated from each other, and operations of the first cell block BLK1and the second cell block BLK2 may be controlled by differentcontrollers.

Cathodes or anodes of the light-emitting cells (refer to 111 in FIG. 4)included in each of the first to ninth cell blocks BLK1 to BLK9 may beelectrically connected to each other. For example, cathodes or anodes ofthe plurality of first light-emitting cells 111_1 included in the firstcell block BLK1 may be electrically connected to each other.

In an example embodiment, the light-emitting cells 111 included in eachof the first to ninth cell blocks BLK1 to BLK9 may be connected inseries to other light-emitting cells 111 within the same block. Forexample, the plurality of first light-emitting cells 111_1 in the firstcell block BLK1 may be connected in series to each other, and theplurality of second light-emitting cells 111_2 in the second cell blockBLK2 may be connected in series to each other. The plurality of firstlight-emitting cells 111_1 in the first cell block BLK1 may beelectrically isolated from the plurality of second light-emitting cells111_2 in the second cell block BLK2. Both ends of each of the pluralityof first light-emitting cells 111_1 and the plurality of secondlight-emitting cells 111_2 may be respectively connected to differentpads.

Because the plurality of first light-emitting cells 111_1 are connectedin series to each other and the plurality of second light-emitting cells111_2 are connected in series to each other, when voltages applied tonodes at which the plurality of first light-emitting cells 111_1 areconnected to each other and nodes at which the plurality of secondlight-emitting cells 111_2 are connected to each other are controlled,operations of the plurality of first light-emitting cells 111_1 and theplurality of second light-emitting cells 111_2 may be controlled.Accordingly, the number of first pads PAD1 connected to the plurality offirst light-emitting cells 111_1 may be less than twice the number offirst light-emitting cells 111_1, and the number of second pads PAD2connected to the plurality of second light-emitting cells 111_2 may beless than twice the number of second light-emitting cells 111_2.

A first controller 210_1 may be electrically connected to a plurality offirst pads PAD1. The first controller 210_1 may adjust voltages appliedto two different pads, from among the plurality of first pads PAD1, andthus, one light-emitting cell of which a cathode and an anode arerespectively connected to the two pads may be driven. For example, thefirst controller 210_1 may adjust a brightness of each of the firstlight-emitting cells 111_1 using a pulse width modulation (PWM) scheme.That is, the first controller 210_1 may adjust the brightness of each ofthe plurality of first light-emitting cells 111_1 by modulating a pulsewidth of a voltage applied to each of the plurality of first pads PAD1.

A second controller 210_2 may be electrically connected to a pluralityof second pads PAD2. The second controller 210_2 may adjust voltagesapplied to two different pads, from among the plurality of second padsPAD2, and thus, one light-emitting cell of which a cathode and an anodeare respectively connected to the two pads may be driven.

According to an order in which the first cell block BLK1 and the secondcell block BLK2 are arranged, the plurality of first pads PAD1 and theplurality of second pads PAD2 corresponding respectively to the firstcell block BLK1 and the second cell block BLK2 may be arranged insequential order. The first cell block BLK1 and the plurality of firstpads PAD1 may be arranged in parallel and extend along a seconddirection Y, and the second cell block BLK2 and the plurality of secondpads PAD2 may be arranged in parallel and extend along the seconddirection Y.

Referring to FIG. 6, a first cell block BLK1′ may further include aplurality of first light-emitting cells 111_1 and a dummy light-emittingcell 111_1′, each of which is implemented as an LED. The dummylight-emitting cell 111_1′ may not be connected to the plurality offirst pads PAD1 and may not substantially operate. In an exampleembodiment, the number of first light-emitting cells 111_1 and the dummylight-emitting cell 111_1′ included in the first cell block BLK1′ may beequal to the number of second light-emitting cells 111_2 included in thesecond cell block BLK2.

FIGS. 7 to 9 are diagrams of a light-emitting device 100 according toexample embodiments. FIG. 7 is an enlarged plan view of region BX ofFIG. 4. FIG. 7 illustrates an example of the light-emitting device 100,in which a first cell block does not include a dummy light-emitting cellas shown in FIG. 5. FIG. 8 is an enlarged cross-sectional view ofconfigurations of some components, which is taken along line II-II′ ofFIG. 7, according to an example embodiment. FIG. 9 is an enlarged viewof region CX2 of FIG. 8.

Referring to FIGS. 7 to 9, a partition wall structure WS may be on aplurality of light-emitting structures 120. As shown in FIG. 7, thepartition wall structure WS may include a plurality of partition wallsWSI and an outer partition wall WSO. The plurality of partition wallsWSI may define a plurality of cell spaces PXS in a cell array regionPXR, and the outer partition wall WSO may be on outermost edges of theplurality of partition walls WSI. Light-emitting cells may berespectively disposed in the plurality of cell spaces PXS.

The partition wall structure WS may include round-corner sidewall unitsPWC facing the plurality of cell spaces PXS. The plurality of cellspaces PXS having corners rounded by the round-corner sidewall units PWCof the partition wall structure WS may be respectively defined.

Each of the plurality of partition walls WSI may have a first width w11of about 10 μm to about 100 μm in a lateral direction (i.e., a seconddirection Y). The outer partition wall WSO may have a second width w12of about 10 μm to about 1 mm in the lateral direction (i.e., the seconddirection Y). The partition wall structure WS may be formed such thatthe outer partition wall WSO is formed to have the second width w12greater than the first width w11 of the plurality of partition wallsWSI. Thus, the structural stability of the light-emitting device 100 maybe improved. For example, even when repetitive vibration and impact areapplied to the light-emitting device 100 when the light-emitting device100 is used as a headlamp for a vehicle, the reliability of thelight-emitting device 100 may be improved by excellent structuralstability between the partition wall structures WS and the fluorescentlayer 160 positioned within the partition wall structures WS.

Each of the plurality of light-emitting structures 120 may include afirst conductive semiconductor layer 122, an active layer 124, and asecond conductive semiconductor layer 126. An insulating liner 132, afirst contact 134A, a second contact 134B, and a wiring structure 140may be on a bottom surface of each of the plurality of light-emittingstructures 120.

For brevity, as shown in FIG. 9, a surface of the light-emittingstructure 120, which faces the plurality of partition walls WSI, may bereferred to as a top surface of the light-emitting structure 120, whilea surface of the light-emitting structure 120 opposite to the topsurface of the light-emitting structure 120 (i.e., a surface of thelight-emitting structure 120 positioned far from the plurality ofpartition walls WSI) may be referred to as a bottom surface of thelight-emitting structure 120. For example, the first conductivesemiconductor layer 122, the active layer 124, and the second conductivesemiconductor layer 126 may be stacked in the vertical direction (i.e.,a third direction (Z)) from the top surface of the light-emittingstructure 120 to the bottom surface thereof. Thus, the top surface ofthe light-emitting structure 120 may correspond to a top surface of thefirst conductive semiconductor layer 122, and the bottom surface of thelight-emitting structure 120 may correspond to a bottom surface of thesecond conductive semiconductor layer 126.

The first conductive semiconductor layer 122 may be a nitridesemiconductor having a composition of n-type In_(x)Al_(y)Ga_((1-x-y))N(where 0≤x<1, 0≤y<1, and 0≤x+y<1). For example, the n-type impuritiesmay be silicon (Si). For example, the first conductive semiconductorlayer 122 may include GaN containing n-type impurities.

In example embodiments, the first conductive semiconductor layer 122 mayinclude a first conductive semiconductor contact layer and a currentdiffusion layer. An impurity concentration of the first conductivesemiconductor contact layer may be in a range of 2×10¹⁸ cm⁻³ to 9×10¹⁹cm⁻³. A thickness of the first conductive semiconductor contact layermay be about 1 μm to about 5 μm. The current diffusion layer may have astructure in which a plurality of In_(x)Al_(y)Ga_((1-x-y))N layers(where 0≤x, y<1, and 0≤x+y<1) having different compositions or differentimpurity contents are alternately stacked. For example, the currentdiffusion layer may have an n-type superlattice structure in whichn-type GaN layers and/or Al_(x)In_(y)Ga_(z)N layers (where 0≤x,y,z≤1,and x+y+z≠0) each having a thickness of about 1 nm to about 500 nm arealternately stacked. An impurity concentration of the current diffusionlayer may be in the range of 2×10¹⁸ cm⁻³ to 9×10¹⁹ cm⁻³.

The active layer 124 may be interposed between the first conductivesemiconductor layer 122 and the second conductive semiconductor layer126. The active layer 124 may discharge light having some energy byrecombination of electrons and holes during the driving of thelight-emitting device 100. The active layer 124 may have a multiplequantum well (MQW) structure in which quantum well layers and quantumbarrier layers are alternately stacked. For example, each of the quantumwell layers and each of the quantum barrier layers may includeIn_(x)Al_(y)Ga_((1-x-y))N layers (where 0≤x, y≤1, and 0≤x+y≤1) havingdifferent compositions. For example, the quantum well layer may includeIn_(x)Ga_(1-x)N (where 0≤x≤1), and the quantum barrier layer may includeGaN or AlGaN. Thicknesses of the quantum well layer and the quantumbarrier layer may be in the range of about 1 nm to about 50 nm. Theactive layer 124 is not limited to having the MQW structure and may havea single quantum well structure.

The second conductive semiconductor layer 126 may include a nitridesemiconductor layer having a composition of p-typeIn_(x)Al_(y)Ga_((1-x-y))N (where 0≤x<1, 0≤y<1, and 0≤x+y≤1). Forexample, the p-type impurities may be magnesium (Mg).

In example embodiments, the second conductive semiconductor layer 126may include an electron blocking layer, a low-concentration p-type GaNlayer, and a high-concentration p-type GaN layer, which are stacked in avertical direction. For example, the electron blocking layer may have astructure in which a plurality of In_(x)Al_(y)Ga_((1-x-y))N layers(where 0≤x, y≤1, and 0≤x+y≤1) having a thickness of about 5 nm to about100 nm and having different compositions are alternately stacked, or mayinclude a single layer including Al_(y)Ga_((1-y))N (where 0<y≤1). Anenergy band gap of the electron blocking layer may be reduced in adirection away from the active layer 124. For example, aluminum (Al)content in the electron blocking layer may be reduced in the directionaway from the active layer 124.

Each of the plurality of light-emitting structures 120 may be spacedapart from light-emitting structures 120 adjacent thereto with a deviceisolation region IA interposed therebetween. A distance s11 between theplurality of light-emitting structures 120 may be less than the firstwidth w11 of each of the plurality of partition walls WSI, without beinglimited thereto.

The insulating liner 132 may be positioned to conformally cover an innerwall of the device isolation region IA and a side surface of each of theplurality of light-emitting structures 120. Also, the insulating liner132 may be on an inner wall of the opening E, which completely passesthrough the active layer 124 and the second conductive semiconductorlayer 126. In example embodiments, the insulating liner 132 may includesilicon oxide, silicon oxynitride, or silicon nitride. In some exampleembodiments, the insulating liner 132 may have a structure in which aplurality of insulating layers are stacked.

The first contact 134A may be connected to the first conductivesemiconductor layer 122 in the opening E penetrating the active layer124 and the second conductive semiconductor layer 126. The secondcontact 134B may be on the bottom surface of the second conductivesemiconductor layer 126. The insulating liner 132 may electricallyinsulate the first contact 134A from the active layer 124 and the secondconductive semiconductor layer 126. The insulating liner 132 may beinterposed between the first contact 134A and the second contact 134B onthe bottom surface of the second conductive semiconductor layer 126 andelectrically insulate the first contact 134A from the second contact134B. Each of the first contact 134A and the second contact 234B mayinclude silver (Ag), aluminum (Al), nickel (Ni), chromium (Cr), gold(Au), platinum (Pt), palladium (Pd), tin (Sn), tungsten (W), rhodium(Rh), iridium (Ir), ruthenium (Ru), magnesium (Mg), zinc (Zn), titanium(Ti), copper (Cu), or a combination thereof. Each of the first contact134A and the second contact 134B may include a metal material havinghigh reflectivity.

A lower reflective layer 136 may be on the insulating liner 132positioned on the inner wall of the device isolation region IA. Thelower reflective layer 136 may reflect light emitted from sidewalls ofthe plurality of light-emitting structures 120 and direct the reflectedlight into the plurality of cell spaces PXS.

In example embodiments, the lower reflective layer 136 may include Ag,Al, Ni, Cr, Au, Pt, Pd, Sn, W, Rh, Ir, Ru, Mg, Zn, Ti, Cu, or acombination thereof. The lower reflective layer 136 may include a metalmaterial having high reflectivity. In other example embodiments, thelower reflective layer 136 may include a distributed Bragg reflector(DBR). For example, the DBR may have a structure in which a plurality ofinsulating layers having different refractive indexes are repeatedlystacked. Each of the insulating layers in the DBR may include oxide,nitride, or a combination thereof, for example, SiO₂, SiN, SiO_(x)N_(y),TiO₂, Si₃N₄, Al₂O₃, TiN, AlN, ZrO₂, TiAlN, or TiSiN.

A wiring structure 140 may be on the insulating liner 132, the firstcontact 134A, the second contact 134B, and the lower reflective layer136. The wiring structure 140 may include a plurality of insulatinglayers 142 and a plurality of wiring layers 144. The plurality of wiringlayers 144 may electrically connect each of the first contact 134A andthe second contact 134B to the pad PAD. Some of the plurality of wiringlayers 144 may be on the inner wall of the device isolation region IA,and the plurality of insulating layers 142 may respectively cover theplurality of wiring layers 144 and fill the device isolation region IA.As shown in FIG. 9, the plurality of wiring layers 144 may include atleast two wiring layers 144 located at different levels in the verticaldirection, but example embodiments are not limited thereto. Each of theplurality of wiring layers 144 may include Ag, Al, Ni, Cr, Au, Pt, Pd,Sn, W, Rh, Ir, Ru, Mg, Zn, Ti, Cu, or a combination thereof.

In example embodiments, the plurality of wiring layers 144 mayelectrically connect the first contact 134A of one light-emittingstructure 120 to the second contact 134B of another light-emittingstructure 120 connected in series to the one light-emitting structure120 so that the plurality of light-emitting cells included in one cellblock may be connected in series to each other.

Alternatively, in contrast to the illustration of FIG. 8, in anotherexample embodiment, the plurality of wiring layers 144 may electricallyconnect the first contact 134A of one light-emitting structure 120 tothe first contact 134A of another light-emitting structure 120 connectedin parallel to the one light-emitting structure 120 so that theplurality of light-emitting cells included in one cell block may beconnected in parallel to each other.

The pad PAD may be in the pad region PDR and connected to the pluralityof wiring layers 144. The pad PAD may be at a lower level than thepartition wall structure WS. In example embodiments, a sidewall and abottom surface of the pad PAD may be covered by the plurality ofinsulating layers 142, and a top surface of the pad PAD may be at alower level than the top surfaces of the plurality of light-emittingstructures 120. In other example embodiments, in contrast to theillustration of FIG. 8, some of the plurality of light-emittingstructures 120 may be in the pad region PDR, and the pad PAD may be inopenings formed in the plurality of light-emitting structures 120. Inthis case, the top surface of the pad PAD may be at the same level asthe top surfaces of the plurality of light-emitting structures 120.Connection members (e.g., bonding wires) for electrical connection witha controller may be on the pad PAD.

The partition wall structures WS may be on the top surfaces of theplurality of light-emitting structures 120. The partition wallstructures WS may include silicon (Si), silicon carbide (SiC), sapphire(Al₂O₃), or gallium nitride (GaN). In an example process, after theplurality of light-emitting structures 120 are formed on a substrate(refer to 110 in FIG. 18A), the partition wall structures WS may beformed by removing portions of the substrate 110. In this case, thepartition wall structures WS may be portions of the substrate 110, whichserve as a growth substrate for forming the light-emitting structures120.

The plurality of partition walls WSI may be arranged in a matrix form ina plan view, and the plurality of cell spaces PXS may be defined by theplurality of partition walls WSI. Each of the plurality of partitionwalls WSI may include a recess region RS, which is at a bottom of eachof the plurality of partition walls WSI to vertically overlap the deviceisolation region IA. The recess region RS may be formed by removing aportion of the substrate 110 during an etching process for separating alight-emitting stack into the plurality of light-emitting structures120. The insulating liner 132 may be arranged to contact the recessregion RS on a bottom surface of each of the plurality of partitionwalls WSI.

The top surfaces of the plurality of light-emitting structures 120 maybe exposed at bottoms of the plurality of cell spaces PXS. For example,concave/convex portions 120P may be formed in the top surfaces of theplurality of light-emitting structures 120 positioned at the bottoms ofthe plurality of cell spaces PXS. Light extraction efficiency of theplurality of light-emitting structures 120 may be improved by theconcave/convex portions 120P, but example embodiments are not limitedthereto.

A passivation structure 150 may be on a top surface WST and a sidewallWSS of each of the plurality of partition walls WSI. The passivationstructure 150 may include a first passivation layer 152 and a secondpassivation layer 154, which are conformally on the top surface WST andthe sidewall WSS of each of the plurality of partition walls WSI. Thepassivation structure 150 may also be conformally on the top surfaces ofthe light-emitting structures 120 (e.g., on the concave/convex portions120P) positioned at the bottoms of the plurality of cell spaces PXS.Although FIG. 8 illustrates two passivation layers (e.g., 152 and 154),example embodiments are not limited thereto, and the passivationstructure 150 may include three or more passivation layers.

In example embodiments, the first passivation layer 152 may include afirst insulating material, and the second passivation layer 154 mayinclude a second insulating material that is different from the firstinsulating material. Each of the first insulating material and thesecond insulating material may include at least one of silicon oxide,silicon nitride, silicon oxynitride, aluminum oxide, and aluminumnitride.

In example embodiments, the passivation structure 150 may include afirst portion 150P1 positioned on the top surface WST of each of theplurality of partition walls WSI, a second portion 150P2 positioned onthe sidewall WSS of each of the plurality of partition walls WSI, and athird portion 150P3 positioned on the top surfaces of the plurality oflight-emitting structures 120. In some example embodiments, a firstthickness t11 of the first portion 150P1 may be less than or equal to asecond thickness t12 of the second portion 150P2. Also, a thirdthickness t13 of the third portion 150P3 may be less than or equal tothe second thickness t12 of the second portion 150P2. In some exampleembodiments, the first thickness t11 of the first portion 150P1 may bein a range of about 0.1 μm to about 2 μm, and the second thickness t12of the second portion 150P2 may be in a range of about 0.5 μm to about 5μm.

As shown in FIG. 9, portions of the first passivation layer 152 includedin the first portion 150P1 (i.e., portions of the first passivationlayer 152 on the top surfaces WST of the plurality of partition wallstructures WS) may have a thickness less than a thickness of portions ofthe first passivation layer 152 included in the second portion 150P2(i.e., portions of the first passivation layer 152 on the sidewalls WSSof the plurality of partition wall structures WS). Similarly, portionsof the second passivation layer 154 included in the first portion 150P1(i.e., portions of the second passivation layer 154 on the top surfacesWST of the plurality of partition wall structures WS) may have athickness less than a thickness of portions of the second passivationlayer 154 included in the second portion 150P2 (i.e., portions of thesecond passivation layer 154 on the sidewalls WSS of the plurality ofpartition wall structures WS).

In example embodiments, the first passivation layer 152 may have arelatively uniform thickness on the sidewall WSS of each of theplurality of partition walls WSI. Here, the expression “relativelyuniform thickness” may mean that a minimum thickness of the firstpassivation layer 152 positioned on the sidewall WSS of each of theplurality of partition walls WSI is within about 10% of a maximumthickness thereof. Also, the second passivation layer 154 may have arelatively uniform thickness on the sidewall WSS of each of theplurality of partition walls WSI. In an example manufacturing process,the first and second passivation layers 152 and 154 may be formed usinga material having excellent step coverage characteristics or amanufacturing process (e.g., an atomic layer deposition (ALD) process),which is advantageous in forming materials having excellent stepcoverage characteristics.

For example, the first thickness t11 may be less than a criticalthickness for the passivation structure 150 to act as a light guide. Forexample, when the first thickness t11 of the first portion 150P1 of thepassivation structure 150 positioned on the top surface WST of each ofthe plurality of partition walls WSI is greater than the criticalthickness, light emitted from one light-emitting cell may be directedinto an adjacent light-emitting cell through the first portion 150P1 ofthe passivation structure 150. Accordingly, when one light-emitting cellis turned on, light may be absorbed or penetrated into a light-emittingcell adjacent thereto, and thus, the adjacent light-emitting cell may bedifficult to be put into a complete off state. When the first thicknesst11 of the first portion 150P1 is less than the critical thickness,light emitted from one light-emitting cell may be blocked from anadjacent light-emitting cell through the first portion 150P1 of thepassivation structure 150. The first thickness t11 of the first portion150P1 may be less than or equal to the second thickness t12 of thesecond portion 150P2. Particularly, the first thickness t11 of the firstportion 150P1 may be less than the critical thickness for thepassivation structure 150 to act as the light guide. Accordingly, thesecond portion 150P2 of the passivation structure 150 may provide asufficient thickness to prevent contamination of the fluorescent layer160, while undesired light crosstalk between adjacent pixels PX due tothe first portion 150P1 of the passivation structure 150 may beprevented.

A fluorescent layer 160 may be inside the plurality of cell spaces PXSon the top surfaces of the plurality of light-emitting structures 120.As shown in FIG. 8, the fluorescent layer 160 may substantially fill thetotal space of the plurality of cell spaces PXS on the passivationstructure 150. A top surface of the fluorescent layer 160 may be at thesame level as the top surface WST of each of the plurality of partitionwalls WSI, but example embodiments are not limited thereto.

The fluorescent layer 160 may include a single material capable ofconverting the color of light emitted from the light-emitting structure120 into a desired color. That is, a fluorescent layer 160 associatedwith the same color may be in the plurality of cell spaces PXS. However,example embodiments are not limited thereto. The color of a fluorescentlayer 160 in some of the plurality of cell spaces PXS may be differentfrom the color of a fluorescent layer 160 in the remaining cell spacesPXS.

The fluorescent layer 160 may include a resin containing a fluorescentmaterial dispersed therein or a film containing a fluorescent material.For example, the fluorescent layer 160 may include a fluorescentmaterial film in which fluorescent material particles are uniformlydispersed at a certain concentration. The fluorescent material particlesmay be a wavelength conversion material that changes the wavelength oflight emitted from the plurality of light-emitting structures 120. Thefluorescent layer 160 may include at least two kinds of fluorescentmaterial particles having different size distributions to improve thedensity and color uniformity of the fluorescent material particles.

In example embodiments, the fluorescent material may have various colorsand various compositions such as an oxide-based composition, asilicate-based composition, a nitride-based composition, and afluoride-based composition. For example, β-SiAlON:Eu²⁺ (green), (Ca,Sr)AlSiN₃:Eu²⁺ (red), La₃Si₆N₁₁:Ce³⁺ (yellow), K₂SiF₆:Mn₄ ⁺(red),SrLiAl₃N₄:Eu(red),Ln_(4-x)(Eu_(z)M_(1-z))_(x)Si_(12-y)Al_(y)O_(3+x+y)N_(18-x-y)(0.5≤x≤3,0<z<0.3, 0<y≤4)(red), K₂TiF₆:Mn₄ ⁺(red), NaYF₄:Mn₄ ⁺ (red), NaGdF₄:Mn₄⁺(red), and the like may be used as the fluorescent material. However,the kind of the fluorescent material is not limited thereto.

In other example embodiments, a wavelength conversion material, such asa quantum dot, may be further positioned over the fluorescent layer 160.The quantum dot may have a core-shell structure using a III-V or II-VIcompound semiconductor. For example, the quantum dot may have a coresuch as CdSe and InP and a shell such as ZnS and ZnSe. In addition, thequantum dot may include a ligand for stabilizing the core and the shell.

A support substrate 170 may be on the wiring structure 140, and anadhesive layer 172 may be interposed between the support substrate 170and the wiring structure 140. In example embodiments, the adhesive layer172 may include an electrically insulating material, for example,silicon oxide, silicon nitride, a polymer material such as anultraviolet (UV)-curable material, or resin. In some exampleembodiments, the adhesive layer 172 may include a eutectic adhesivematerial, such as AuSn or NiSi. The support substrate 170 may include asapphire substrate, a glass substrate, a transparent conductivesubstrate, a silicon substrate, or a silicon carbide substrate, but isnot limited thereto.

In general, a light source module including a plurality oflight-emitting device chips may be used for an intelligent lightingsystem (e.g., a head lamp for a vehicle), and each of the light-emittingdevice chips may be individually controlled to implement variouslighting modes depending on surrounding conditions. When a plurality oflight-emitting devices arranged in a matrix form are used, light emittedfrom each of the plurality of light-emitting devices may be absorbed orpenetrated into a light-emitting device adjacent thereto. Thus, contrastcharacteristics of the light source module may be poor. However,according to example embodiments, by forming the partition wallstructures WS on the plurality of light-emitting structures 120, theabsorption or penetration of light emitted from one light-emitting cellinto an adjacent light-emitting cell may be reduced or prevented.

During a process of forming a passivation layer covering the partitionwall structure WS, a thickness of a portion of the passivation layer,which is formed on the top surface of the partition wall structure WS,may be greater than a thickness of a portion of the passivation layer,which is formed on a sidewall of the partition wall structure WS. Inthis case, the portion of the passivation layer, which is formed on thetop surface of the partition wall structure WS, may act as a lightguide, and thus, light emitted from one light-emitting cell may beadsorbed or penetrated into an adjacent light-emitting cell. However,according to example embodiments, the first portion 150P1 of thepassivation structure 150 may be formed to a thickness less than orequal to a thickness of the second portion 150P2 thereof. Thus, theabsorption or penetration of light emitted from one light-emitting cellinto an adjacent light-emitting cell through the first portion 150P1 ofthe passivation structure 150 may be prevented or reduced. Accordingly,contrast characteristics of the light-emitting device 100 may beexcellent.

In addition, the fluorescent layer 160 may be firmly fixed in each ofthe cell spaces PXS by the partition wall structure WS. Even whenrepetitive vibration and impact are applied to the light-emitting device100 when the light-emitting device 100 is used as a headlamp for avehicle, the reliability of the light-emitting device 100 may beimproved.

FIGS. 10 and 11 are circuit diagrams for explaining a connectionrelationship between light-emitting cells included in a light-emittingdevice 100 according to an example embodiment. FIGS. 10 and 11 areequivalent circuit diagrams of the first cell block BLK1 and the secondcell block BLK2 of FIG. 4, according to example embodiments. In FIGS. 10and 11, one light-emitting cell may correspond to one diode. Thedescription of the first and second cell blocks BLK1 and BLK2 of FIGS.10 and 11 may be equally applied to the third to ninth cell blocks BLK3to BLK9 of FIG. 4.

Referring to FIGS. 4 and 10, a first cell block BLK1A may include aplurality of first light-emitting cells 111_1A, each of which isimplemented as an LED, and a second cell block BLK2A may include aplurality of second light-emitting cells 111_2A, each of which isimplemented as an LED. The number of first light-emitting cells 111_1 Amay be less than the number of second light-emitting cells 111_2A. Thefirst cell block BLK1A and the second cell block BLK2A may beelectrically insulated from each other, and operations of the first cellblock BLK1A and the second cell block BLK2A may be controlled bydifferent controllers.

In an example embodiment, the light-emitting cells 111 included in eachof the first to ninth cell blocks BLK1A to BLK9 may be connected inparallel to other light-emitting cells 111 within the same block. Forexample, the plurality of first light-emitting cells 111_1A included inthe first cell block BLK1A may be connected in parallel to each other,and the plurality of second light-emitting cells 111_2A included in thesecond cell block BLK2A may be connected in parallel to each other. Oneend of each of the plurality of first light-emitting cells 111_1A andthe plurality of second light-emitting cells 111_2A may be respectivelyconnected to different pads, and another end of each of the plurality offirst light-emitting cells 111_1A and the plurality of secondlight-emitting cells 111_2A may be connected to a common pad.

Anodes of the plurality of first light-emitting cells 111_1 A may beconnected to each other, and anodes of the plurality of secondlight-emitting cells 111_2A may be connected to each other. In contrastto the illustration of FIG. 10, cathodes of the plurality of firstlight-emitting cells 111_1A may be connected to each other, and cathodesof the plurality of second light-emitting cells 111_2A may be connectedto each other. The number of first pads PAD1A connected to the pluralityof first light-emitting cells 111_1A may be less than twice the numberof first light-emitting cells 111_1A. The number of second pads PAD2Aconnected to the plurality of second light-emitting cells 111_2A may beless than twice the number of second light-emitting cells 111_2A.

A first controller may be electrically connected to the plurality offirst pads PAD1A. The first controller may adjust voltages applied totwo different pads, from among the plurality of first pads PAD1A, anddrive one light-emitting cell of which a cathode and an anode arerespectively connected to the two pads. A second controller may adjustvoltages applied to two different pads, from among the plurality ofsecond pads PAD2A, and drive one light-emitting cell of which a cathodeand an anode are respectively connected to the two pads.

Referring to FIG. 11, a first cell block BLK1A′ may further include aplurality of first light-emitting cells 111_1A and a dummylight-emitting cell 111_1A′, each of which is implemented as an LED. Thedummy light-emitting cell 111_1A′ may not be connected to a plurality offirst pads PAD1A and may not substantially operate. In an exampleembodiment, the number of first light-emitting cells 111_1A and thedummy light-emitting cell 111_1A′ included in the first cell blockBLK1A′ may be equal to the number of second light-emitting cells 111_2Aincluded in the second cell block BLK2.

FIG. 12 is a cross-sectional view of a light-emitting device 300according to example embodiments. FIG. 13 is an enlarged view of regionCX4 of FIG. 12. FIG. 12 is an enlarged cross-sectional view of somecomponents of the light-emitting device 300 adhered onto a printedcircuit board 370, which is taken along line II-II′ of FIG. 7, accordingto an example embodiment. In the descriptions of FIGS. 12 and 13,repeated descriptions of the same reference numerals as given withrespect to FIGS. 8 and 9 are omitted.

Referring to FIGS. 12 and 1, the light-emitting device 300 may furtherinclude a buffer structure BS provided between a first conductivesemiconductor layer 122 and a partition wall structure WS. The bufferstructure BS may include a nucleation layer 310, a dislocation-removingstructure 320, and a buffer layer 330, which are sequentially arrangedon a bottom surfaces of the partition wall structure WS toward the firstconductive semiconductor layer 122. The dislocation-removing structure320 may include a first dislocation-removing material layer 322 and asecond dislocation-removing material layer 324.

In example embodiments, the nucleation layer 310 may be a layer forforming nuclei for crystal growth or assisting the wetting of thedislocation-removing structures 320. For example, the nucleation layer310 may include aluminum nitride (AlN). The first dislocation-removingmaterial layer 322 may include B_(x)Al_(y)InzGa_(1-x-y-z)N (where 0≤x<1,0<y<1, 0≤z<1, and 0≤x+y+z<1). In some example embodiments, an aluminum(Al) content of the first dislocation-removing material layer 322 may beabout 25 atomic percent (at %) to about 75 at %. The seconddislocation-removing material layer 324 may have a different latticeconstant from the first dislocation-removing material layer 322 andinclude, for example, aluminum nitride (AlN). At an interface betweenthe first and second dislocation-removing material layers 322 and 324, adislocation may be bent or a dislocation half-loop may be formed due toa difference in lattice constant between the first and seconddislocation-removing material layers 322 and 324 to reduce thedislocation. A thickness of the second dislocation-removing materiallayer 324 may be less than a thickness of the nucleation layer 310.Thus, tensile stress generated in the second dislocation-removingmaterial layer 324 may be reduced to prevent cracks from occurring.

The buffer layer 330 may reduce differences in lattice constant andcoefficient of thermal expansion (CTE) between a layer (e.g., the firstconductive semiconductor layer 122) formed on the buffer structure BSand the second dislocation-removing material layer 324. For example, thebuffer layer 330 may include B_(x)Al_(y)In_(z)Ga_(1-x-y-z)N (where0≤x<1, 0<y<1, 0≤z<1, and 0≤x+y+z<1).

According to example embodiments, the buffer structure BS may not onlyprevent cracks from occurring in a plurality of light-emittingstructures 120 but also prevent the propagation of dislocations into theplurality of light-emitting structures 120. Thus, the crystal quality ofthe light-emitting structures 120 may be improved.

In example embodiments, a wiring structure 140 may be arranged over atop surface of a support structure 360 with a first adhesive layer 352therebetween, and a printed circuit board (PCB) 370 may be arranged on abottom surface of the support structure 360 with a second adhesive layer354 therebetween. The support structure 360 may include a supportsubstrate 362, a first insulating layer 364, and a second insulatinglayer 366. The first insulating layer 364 may be in contact with thefirst adhesive layer 352, and the second insulating layer 366 may be incontact with the second adhesive layer 354.

The support substrate 362 may include an insulating substrate or aconductive substrate. The support substrate 362 may have an electricresistance of at least several MΩ, for example, at least 50 MΩ. Forexample, the support substrate 362 may include doped silicon, undopedsilicon, Al₂O₃, tungsten (W), copper (Cu), a bismaleimide triazine (BT)resin, an epoxy resin, polyimide, a liquid crystal (LC) polymer, acopper clad laminate, or a combination thereof. The support substrate362 may have a thickness of at least 150 μm (e.g., about 200 μm to about400 μm) in a vertical direction (i.e., a Z direction).

Each of the first insulating layer 364 and the second insulating layer366 may have an electric resistance of at least several tens of MΩ, forexample, at least 50 MΩ. For instance, each of the first insulatinglayer 364 and the second insulating layer 366 may include at least oneof SiO₂, Si₃N₄, Al₂O₃, HfSiO₄, Y₂O₃, ZrSiO₄, HfO₂, ZrO₂, Ta₂O₅, andLa₂O₃.

According to example embodiments, because the support structure 360 hasa relatively high electric resistance, the occurrence of failures due tothe formation of an undesired conduction path from the wiring structure140 through the support structure 360 to the PCB 370 in a verticaldirection may be prevented.

FIG. 14 is a cross-sectional view of a light-emitting package 1000including a light-emitting device 100, according to an exampleembodiment. In FIG. 14, the same reference numerals are used to denotethe same elements as in FIGS. 1 to 13.

Referring to FIG. 14, the light-emitting package 1000 may include thelight-emitting device 100 and a semiconductor driving chip 210, whichare mounted on a package substrate 410. The semiconductor driving chip210 may be one of the first to ninth controllers 210_1 to 210_9 of FIG.2, and the package substrate 410 may be a printed circuit board PCB ofFIG. 2.

A lower insulating layer 412, an inner conductive pattern layer 413, andan upper insulating layer 414 may be sequentially stacked on a partialregion of a base plate 411, and at least one driver semiconductor chip210 may be mounted on a conductive pattern positioned on the upperinsulating layer 414.

An interposer 450 may be on another region of the base plate 411 with anadhesive layer 440 therebetween, and the light-emitting device 100 maybe mounted on the interposer 450. In example embodiments, the interposer450 may be the same as the support substrate (refer to 170 in FIG. 8)included in the light-emitting device 100, but is not limited thereto.The at least one semiconductor driving chip 210 may be electricallyconnected to a pad PAD of the light-emitting device 100 through abonding wire 480 connected to a pad 470. The at least one semiconductordriving chip 210 may individually or entirely drive a plurality oflight-emitting cells of the light-emitting device 100.

The bonding wire 480 may be encapsulated by a molding resin 460. Themolding resin 460 may include, for example, an epoxy molding compound(EMC), but is not specifically limited. The molding resin 460 maypartially encapsulate the light-emitting device 100 so as not tointerfere with light emitted from the plurality of light-emitting cellsof the light-emitting device 100.

A heat sink 420 may be adhered onto a bottom surface of the base plate411, and a TIM layer 430 may be selectively further positioned betweenthe heat sink 420 and base plate 411.

The light-emitting devices and/or the light source module described withreference to FIGS. 1 to 13 may be mounted alone or in combination in thelight-emitting package 1000.

FIG. 15 is a cross-sectional view of a light-emitting package 1000Aincluding a light-emitting device 100A, according to an exampleembodiment.

Referring to FIG. 15, a conductive line CL may electrically connect afirst contact 134A of one light-emitting structure (e.g. light-emittingstructure 120 of the FIGS. 8, 9, 12) to a second contact 134B of anotherlight-emitting structure 120 connected in series to a specificlight-emitting structure so that a plurality of light-emitting cellsincluded in one cell block are connected in series to each other.Alternatively, in an example embodiment, the conductive line CL mayelectrically connect the first contact 134A of one light-emittingstructure 120 to the first contact 134A of another light-emittingstructure 120 connected in parallel to the one light-emitting structure120 so that a plurality of light-emitting cells included in one cellblock are connected in parallel to each other.

The conductive line CL may not be formed only in the light-emittingdevice 100A. For example, the conductive line CL may include aconductive pattern formed in a package substrate 410. The conductiveline CL may include a conductive pattern formed in an interposer 450.

In an example embodiment, the light-emitting device 100A may not includea plurality of pads, which are formed on an emission surface (e.g., asurface formed in a third direction (Z)). The light-emitting device 100Amay be connected to a semiconductor driving chip 210 through theconductive line CL formed in the package substrate 410.

FIG. 16 is a schematic perspective view of a lighting apparatusincluding a light-emitting device, according to an example embodiment.

Referring to FIG. 16, a headlamp module 2020 may be installed in aheadlamp unit 2010 of a vehicle. A side mirror lamp module 2040 may beinstalled in an outer side mirror unit 2030, and a tail lamp module 2060may be installed in a tail lamp unit 2050. At least one of the headlampmodule 2020, the side mirror lamp module 2040, and the tail lamp module2060 may include one of the light source modules 10 and 10A, whichincludes at least one of the light-emitting devices 100 and 100Adescribed above.

FIG. 17 is a schematic perspective view of a flat-panel lightingapparatus 2100 including a light-emitting device, according to anexample embodiment.

Referring to FIG. 17, the flat-panel lighting apparatus 2100 may includea light source module 2110, a power supply 2120, and a housing 2130.

The light source module 2110 may include a light-emitting device arrayas a light source. The light source module 2110 may be one of the lightsource modules 10 and 10A, which includes, as a light source, at leastone of the light-emitting devices 100 and 100A described above. Thelight source module 2110 may have a flat shape as a whole.

The power supply 2120 may be configured to supply power to the lightsource module 2110. The housing 2130 may form an accommodation space foraccommodating the light source module 2110 and the power supply 2120.The housing 2130 may be formed to have a hexahedral shape with oneopened side, but is not limited thereto. The light source module 2110may be positioned to emit light toward the opened side of the housing2130.

FIG. 18 is an exploded perspective view of a lighting apparatus 2200including a light-emitting device, according to an example embodiment.

Referring to FIG. 18, the lighting apparatus 2200 may include a socket2210, a power supply 2220, a heat sink 2230, a light source module 2240,and an optical unit 2250.

The socket 2210 may be configured to be replaceable with an existinglighting apparatus. Power may be supplied to the lighting apparatus 2200through the socket 2210. The power supply 2220 may be dissembled into afirst power supply 2221 and a second power supply 2222. The heat sink2230 may include an internal heat sink 2231 and an external heat sink2232. The internal heat sink 2231 may be directly connected to the lightsource module 2240 and/or the power supply 2220 and transmit heat to theexternal heat sink 2232 through the light source module 2240 and/or thepower supply 2220. The optical unit 2250 may include an internal opticalunit and an external optical unit. The optical unit 2250 may beconfigured to uniformly disperse light emitted by the light sourcemodule 2240.

The light source module 2240 may receive power from the power supply2220 and emit light to the optical unit 2250. The light source module2240 may include at least one light-emitting element package 2241, acircuit board 2242, and a controller 2243. The controller 2243 may storedriving information of the light-emitting device packages 2241. Thelight-emitting device package 2241 may include at least one of thelight-emitting devices 100 and 100A described above, and the lightsource module 2240 may be one of the light source modules 10 and 10Adescribed above.

While example embodiments have been particularly shown and described, itwill be understood that various changes in form and details may be madetherein without departing from the spirit and scope of the followingclaims.

1. A light source module comprising: a printed circuit board; alight-emitting device mounted on the printed circuit board, thelight-emitting device comprising a plurality of cell blocks, each ofwhich comprises a plurality of light-emitting cells; and a plurality ofcontrollers mounted on the printed circuit board, each of which isconfigured to drive a cell block corresponding thereto, from among theplurality of cell blocks, wherein the plurality of cell blocks areelectrically isolated from each other, wherein the plurality of cellblocks comprise a first cell block and a second cell block, and whereina number of first light-emitting cells included in the first cell blockis less than a number of second light-emitting cells included in thesecond cell block.
 2. The light source module of claim 1, wherein theplurality of controllers comprise a first controller and a secondcontroller, wherein the first controller is configured to drive thefirst cell block through first channels, wherein the second controlleris configured to drive the second cell block through second channelswhich are different from the first channels, and wherein a number offirst channels connected to the first controller is equal to a number ofsecond channels connected to the second controller.
 3. The light sourcemodule of claim 1, wherein the light-emitting device is disposed in acentral area of the printed circuit board, and wherein the plurality ofcontrollers are disposed in a peripheral area of the printed circuitboard surrounding the central area.
 4. The light source module of claim1, wherein the first light-emitting cells included in the first cellblock are electrically connected to each other.
 5. The light sourcemodule of claim 4, wherein the first light-emitting cells areelectrically connected to each other in the light-emitting device. 6.The light source module of claim 4, wherein the first light-emittingcells are electrically connected to each other through conductive linesformed on the printed circuit board.
 7. The light source module of claim1, wherein the plurality of cell blocks are arranged in a first row anda second row, and wherein the first cell block is arranged on an end ofthe first row.
 8. The light source module of claim 1, wherein theplurality of cell blocks are arranged in a first row and a second row,and wherein the first cell block is in a center of the second row. 9.The light source module of claim 8, wherein the first cell blockcomprises a smallest number of light-emitting cells from among theplurality of cell blocks.
 10. (canceled)
 11. A light-emitting devicecomprising: a plurality of cell blocks electrically isolated from eachother, each of which comprises a plurality of light-emitting cells; anda plurality of pads configured to electrically connect the plurality ofcell blocks to an external device, wherein the plurality of cell blockscomprise a first cell block and a second cell block, and wherein anumber of first light-emitting cells included in the first cell block isless than a number of second light-emitting cells included in the secondcell block.
 12. The light-emitting device of claim 11, wherein the firstlight-emitting cells are connected in series to each other, and whereinthe second light-emitting cells are connected in series to each other.13. (canceled)
 14. The light-emitting device of claim 11, wherein thefirst light-emitting cells further comprise a dummy light-emitting cellelectrically isolated from the plurality of pads.
 15. The light-emittingdevice of claim 11, wherein the plurality of cell blocks are arranged ina first row and a second row, and wherein a total number oflight-emitting cells included in cell blocks arranged in the first rowis less than a total number of light-emitting cells included in cellblocks arranged in the second row.
 16. The light-emitting device ofclaim 11, wherein the plurality of cell blocks are arranged in a firstrow and a second row, and wherein the first cell block is arranged onone end of the first row.
 17. The light-emitting device of claim 11,wherein the plurality of cell blocks are arranged in a first row and asecond row, and wherein the first cell block is in a center of thesecond row.
 18. The light-emitting device of claim 11, wherein theplurality of cell blocks are disposed in a central area of thelight-emitting device, and wherein the plurality of pads are disposed ina peripheral area of the light-emitting device surrounding the centralarea.
 19. A light source module comprising: a printed circuit board; alight-emitting device mounted on the printed circuit board, thelight-emitting device comprising a plurality of cell blocks, each ofwhich comprises a plurality of light-emitting cells; and a plurality ofcontrollers mounted on the printed circuit board, each of which isconfigured to drive a cell block corresponding thereto, from among theplurality of cell blocks, wherein the plurality of cell blocks areelectrically isolated from each other, and wherein the plurality of cellblocks are arranged in a first row and a second row, and a number oflight-emitting cells included in cell blocks arranged in the first rowis less than a number of light-emitting cells included in cell blocksarranged in the second row.
 20. The light source module of claim 19,wherein two cell blocks arranged on two ends of the first row comprise asmaller number of light-emitting cells than other cell blocks positionedadjacent thereto.
 21. The light source module of claim 19, wherein acell block arranged in a center of the second row comprises a smallernumber of light-emitting cells than other cell blocks positionedadjacent thereto. 22-24. (canceled)
 25. The light source module of claim19, wherein the plurality of light-emitting cells included in one cellblock, from among the plurality of cell blocks, are electricallyconnected to each other through conductive lines formed on the printedcircuit board.